JP2003277589A - Semiconductor sealing epoxy resin molding material and its preparation process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for preparing a semiconductor sealing epoxy resin molding material which shows a good flow property upon packaging a semiconductor and a high package reliability after packaging, even with a high filling factor of an inorganic filler, and a semiconductor sealing epoxy resin molding material. <P>SOLUTION: The semiconductor sealing epoxy resin molding material comprises at least an epoxy resin, a phenol resin, an inorganic filler, a curing accelerator and a coupling agent, wherein the inorganic filler content is ≥90 wt.%. In the preparation process, among the inorganic fillers, inorganic fillers having an average particle size D<SB>50</SB>of ≤0.5 μm are subjected to a shearing force in the presence of the coupling agent to yield ≤10% change of the average particle size. The inorganic fillers are pre-mixed with the rest of the components and heat kneaded. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor encapsulation which is excellent in fluidity during semiconductor encapsulation molding and has excellent package reliability after encapsulation molding even if the filling rate of the inorganic filler is high. TECHNICAL FIELD The present invention relates to a method for producing an epoxy resin molding material for a semiconductor and an epoxy resin molding material for semiconductor encapsulation.

[0002]

2. Description of the Related Art For sealing semiconductor elements such as IC and LSI, epoxy resin molding materials which can be transfer molded are widely used from the viewpoint of reliability and productivity. Epoxy resin molding materials for semiconductor encapsulation include epoxy resins, phenolic resins, curing accelerators, inorganic fillers, release agents, flame retardants,
It is composed of a coupling agent etc., but as a manufacturing method,
After pre-mixing a predetermined amount of the ingredients weighed using a stirring mixer such as a Henschel mixer, a step of heating and kneading using a kneader such as a single screw extruder, a twin screw extruder, a heating roll, a continuous kneader Has been adopted. On the other hand, in response to the trend toward smaller and lighter electronic devices with higher functionality, semiconductor devices are becoming smaller, thinner, and narrower in pitch. There is a strong demand for improvement in solder heat resistance and moisture resistance related to the reliability of a semiconductor device after molding. Therefore, for the purpose of reducing the stress and moisture absorption inside the semiconductor device, the components of the epoxy resin molding material for semiconductor encapsulation are shifting to materials having a high inorganic filler ratio. However, simply increasing the content of the inorganic filler in the molding material not only increases lead frame deformation, gold wire deformation, void generation, and other defects in molding due to fluidity deterioration, but also Also in the above semiconductor package, the adhesion between the lead frame or the semiconductor chip and the sealing epoxy resin is deteriorated, and the package reliability is not improved as expected.

On the other hand, regarding the method of treating the inorganic filler for improving the package reliability after encapsulation molding while increasing the ratio of the inorganic filler, the cornered inorganic filler is rounded. Method (JP-A-63-28210)
No. 9) is disclosed, but these methods have not yet provided sufficient fluidity of the molding material for semiconductor encapsulation.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a semiconductor having excellent flowability during semiconductor encapsulation molding and excellent package reliability after encapsulation molding even if the filling rate of the inorganic filler is high. The present invention provides a method for producing an epoxy resin molding material for encapsulation and an epoxy resin molding material for semiconductor encapsulation.

[0005]

The present invention has been studied in view of such circumstances, and as a result, the average particle diameter D ₅₀ was 0.5 μm.
Shearing force is applied to the following inorganic fillers in the presence of a coupling agent in the range where the rate of change of average particle diameter is 10% or less,
It was newly found that by using this inorganic filler, it is possible to obtain an epoxy resin molding material for semiconductor encapsulation which has good flow and is excellent in package reliability after molding. That is, the present invention provides a method for producing an epoxy resin molding material for semiconductor encapsulation, which comprises an epoxy resin and a phenol resin, an inorganic filler, a curing accelerator, and a coupling agent, and the content of the inorganic filler is 90% by weight or more. Among the fillers, an inorganic filler having an average particle diameter D ₅₀ of 0.5 μm or less is given shear shear force in the range of 10% or less in the change rate of the average particle diameter in the presence of a coupling agent, and the inorganic filler is obtained. Is a method for producing an epoxy resin molding material for semiconductor encapsulation, and an epoxy resin molding material for semiconductor encapsulation, which is characterized by premixing with the remaining components and then heat kneading.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
Examples of the inorganic filler used in the present invention include fused spherical silica, crystalline silica, and silicon nitride, but these may be used alone or in combination. In the present invention,
A part of the inorganic filler is treated by applying shear shear force in the presence of the coupling agent. It is essential that the inorganic filler to be treated has an average particle diameter D ₅₀ of 0.5 μm or less. When the average particle size is 0.5 μm or less, the particles agglomerate with each other, and therefore shear shearing force is used for disintegrating the agglomerates, and the particle size change due to the crushing of the primary particles hardly occurs. On the other hand, when the average particle diameter is 0.5 μm or more, the cohesive force between the particles is small and the shear shearing force is directly used for pulverizing the primary particles, so that a treatment with a small change in particle diameter is very difficult. As mentioned above,
In the present invention, the average particle size of the inorganic filler to be treated is 0.5 μm.
It is necessary that the average particle size is 0.1 μm or less.
It is more preferable that the thickness is m or less.

In the present invention, the rate of change of the average particle size of the inorganic filler to be treated is the average particle size A of the inorganic filler before treatment,
When B is the average particle diameter of the inorganic filler after treatment, (A-
B) / (A) × 100 (%). The shearing force is applied in the range where the change rate of the average particle size is 10% or less.

In the present invention, the particle size distribution of the inorganic filler to be treated is not particularly limited, but when the particle size is 1 μm or more, the pulverization of primary particles proceeds and the particle size change occurs. Easy, 1 μm for example
Less than 95% by weight of particles are preferred.

The equipment for applying the shearing force used in the present invention is not particularly limited, but an automatic mortar, raker, ball mill, centrifugal ball mill, vibrating ball mill, planetary ball mill, roller mill and the like can be used. When the treatment is carried out in the presence of a coupling agent using these facilities, shearing force is generated due to friction between the inorganic fillers or between the inorganic filler and the grinding medium, and the coupling agent rubs against the surface of the inorganic filler. By being spread, it spreads and becomes established.
This improves the wettability between the treated inorganic filler and the resin, and improves the fluidity of the epoxy resin molding material.

In the present invention, as described above, the treatment of the inorganic filler is carried out in the range where the change rate of the average particle diameter is 10% or less.
This means a treatment in which the size and shape of the particles are small. On the other hand, Japanese Patent Application Laid-Open No. 63-282109 discloses that the present invention is characterized in that silica fillers are rubbed against each other by a pressing force from the outside so that the angled particles are rounded. There is. This is a process that involves a large change in size and shape, and is different from the present invention.

The average particle size of the inorganic filler used in the present invention may be measured by a general method, but a so-called light scattering method is used, which is obtained from the intensity of scattered light when light is irradiated to particles floating in a fluid. Can be used.

The epoxy resin used in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule and is solid at room temperature. For example, a bisphenol type epoxy resin. Resin, biphenyl type epoxy resin,
Examples thereof include a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and an alkyl-modified triphenol methane type epoxy resin. These may be used alone or in combination.

As the curing agent used in the present invention, a phenol resin is used and is not particularly limited as long as it is solid at room temperature. For example, phenol novolac resin, cresol novolac resin and dicyclo Pentadiene-modified phenol resin, phenol aralkyl resin, naphtho-aralkyl resin, tempene-modified phenol resin and the like are mentioned, and these may be used alone or in combination.

The curing accelerator used in the present invention serves as a catalyst for a curing reaction that crosslinks the epoxy resin and the phenol resin, and includes an amine compound, an organic sulfonic acid compound,
Examples thereof include imidazole compounds, and these may be used alone or in combination.

The coupling agent used in the present invention is not particularly limited, but an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent can be used. Further, these may be used alone or in combination.

The epoxy resin molding material for semiconductor encapsulation obtained by the present invention contains, in addition to the essential components described above, a coloring agent such as carbon black and a release agent such as carnauba wax, if necessary. A low stress agent such as silicone oil and a flame retardant such as antimony trioxide may be added.

Next, the manufacturing method will be described. The present invention is characterized in that these components are premixed and then heated and kneaded. The premixer used in the present invention is not particularly limited, but a Henschel mixer, a tolero mixer, a kneader having two corrugated shafts rotating, and the like can be used. Further, it is preferable to provide a cooling mechanism so that the premixing can be performed in a temperature range where the resin components are not melted or softened. The heating and kneading machine used in the present invention is not particularly limited, and a single screw extruder including a kneader, a twin screw extruder, a heating roll, a continuous kneader, a Banbury mixer, etc. can be used.

[0018]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Example 1 2.7 parts by weight of epoxy resin [3,3 ′, 5,5′-tetramethylbiphenol diglycidyl ether resin, melting point 103 ° C., epoxy equivalent 195], phenol resin [novolak type phenol resin, 150 ° C.] Melt viscosity at 0.3 Pa. s, hydroxyl equivalent 175]
2.8 parts by weight, brominated bisphenol A type epoxy resin 1.0 part by weight, triphenylphosphine 0.2 part by weight, γ-glycidoxypropyltrimethoxysilane
0.5 parts by weight, carbon black 0.3 parts by weight, carnauba wax 0.5 parts by weight, antimony trioxide 1.
0 parts by weight, spherical fused silica powder 1 (average particle size: 23μ
m, maximum particle diameter: 75 μm) 80 parts by weight, spherical fused silica powder 2 (average particle diameter: 0.42 μm, maximum particle diameter:
1.1 μm, particle size less than 1 μm Component: 99% by weight) 1
A formulation composed of 1 part by weight was designated as basic formulation A.

From the basic compound A, γ-glycidoxypropyltrimethoxysilane and fused spherical silica powder 2 were added to an automatic mortar (capacity 4 liters, rotation speed: pestle 60 rpm,
The treatment was performed in a mortar (6 rpm) for 10 minutes. At this time, the average particle diameters of the raw material fused spherical silica powder 2 and the fused spherical silica powder 2 treated with an automatic mortar were measured by a light scattering method,
The average particle size and the rate of change of the average particle size are shown in Table 1. Combine this with the rest of the ingredients in Basic Blend A (Henschel Mixer (capacity 15 liters, rpm 1000 rpm
m, 10 ° C.) premixed for 5 minutes, meshed in the same direction, twin-screw extrusion kneader (screw diameter D = 30 mm, extruder shaft length = 1 m, kneading disc length = 6 D, screw rotation speed 300 rpm, discharge rate The mixture was heated and kneaded at 20 kg / h). The discharged product was formed into a sheet having a thickness of 2 mm, cooled and pulverized to obtain an epoxy resin molding material. The fluidity and package reliability of the obtained material were evaluated according to the following methods. The results are shown in Table 1.

<Evaluation Method> Fluidity: The spiral flow value of the epoxy resin molding material for semiconductor encapsulation was measured using a transfer molding machine equipped with a mold for spiral flow measurement conforming to EMMI-I-66. . The transfer molding conditions were a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a holding pressure curing time of 120 seconds.

Package reliability: Eight 80 pQFP packages (body size 14 mm × 20 mm, thickness 1.5 m) using the epoxy resin molding material for semiconductor encapsulation
m, semiconductor chip size 9 mm x 9 mm) is sealed and molded (Transfer molding machine conditions: 175 ° C, 70 kg / c)
m ² for 120 seconds) and post-cure at 180 ° C. for 8 hours, and then seal the package at a temperature of 85 ° C. and a relative humidity of 85.
%, 168 hours, IR reflow (240 ° C., 10 seconds) was performed immediately after the treatment, and the presence or absence of package cracks after the IR reflow treatment was visually observed. Then, the presence or absence of interfacial peeling between the sealing resin, the semiconductor chip, and the lead frame was observed with an ultrasonic flaw detector, and the adhesion was evaluated by the number of interfacial peelings.

(Example 2) From the basic compound A, γ-
Glycidoxypropyltrimethoxysilane, fused spherical silica powder 2 in a ball mill (volume 4 liters, rotation speed 65
Processing was carried out for 10 minutes at rpm and a medium diameter of 10 mm). At this time, the average particle size of the fused spherical silica powder 2 as the raw material and the fused spherical silica powder 2 treated by the ball mill were measured by a light scattering method, and the average particle size and the rate of change of the average particle size are shown in Table 1. . This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

Example 3 In the basic compound A, 83 parts by weight of fused spherical silica powder 1 and 2 fused spherical silica powder 2 were used.
To 8 parts by weight, and γ-glycidoxypropyltrimethoxysilane and fused spherical silica powder 2 were placed in an automatic mortar (capacity 4 liters, rotation speed: pestle 60 rpm, mortar 6 rpm) 1
The treatment was carried out for 0 minutes. Fused spherical silica powder 2 which is the raw material at this time and fused spherical silica powder 2 processed in an automatic mortar
The average particle diameter of was measured by a light scattering method, and the average particle diameter and the change rate of the average particle diameter are shown in Table 1. This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

(Example 4) In the basic compound A, the fused spherical silica powder 2 was fused with the fused spherical silica 3 (average particle size of 0.
08 μm, maximum particle size 0.2 μm, particle size less than 1 μm (component: 100% by weight), and the fused spherical silica 3 and γ-glycidoxypropyltrimethoxysilane were used in an automatic mortar (volume 4 liters, rotation speed: pestle 100 rpm). ,
The treatment was performed in a mortar (15 rpm) for 20 minutes. At this time, the average particle size of the fused spherical silica powder 3 as the raw material and the fused spherical silica powder 3 treated with an automatic mortar were measured by a light scattering method, and the average particle size and the rate of change of the average particle size are shown in Table 1. It was This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

(Example 5) In the basic compound A, the fused spherical silica powder 2 was fused with the fused spherical silica 4 (average particle size of 0.
45 μm, maximum particle size 1.8 μm, particle size less than 1 μm component: 91% by weight)
Automatic mortar of γ-glycidoxypropyltrimethoxysilane (volume 4 liters, rotation speed: pestle 60 rpm, mortar 6
(rpm) for 10 minutes. At this time, the average particle size of the fused spherical silica powder 4 as the raw material and the fused spherical silica powder 4 treated with an automatic mortar were measured by a light scattering method, and the average particle size and the change rate of the average particle size are shown in Table 1. It was This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

(Comparative Example 1) From the basic compound A, γ-
Glycidoxypropyltrimethoxysilane and fused spherical silica powder 2 were treated in an automatic mortar (capacity: 4 liters, rotation speed: pestle 100 rpm, mortar: 15 rpm) for 120 minutes. The average particle diameters of the fused spherical silica powder 2 as the raw material and the fused spherical silica powder 2 treated with an automatic mortar at this time were measured by a light scattering method, and the average particle diameter and the rate of change of the average particle diameter are shown in Table 1. It was This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

(Comparative Example 2) From the basic compound A, γ-
Glycidoxypropyltrimethoxysilane, fused spherical silica powder 2 in a ball mill (volume 4 liters, rotation speed 80
Processing was performed for 120 minutes at rpm and media diameter of 15 mm). At this time, the average particle size of the fused spherical silica powder 2 as the raw material and the fused spherical silica powder 2 treated by the ball mill were measured by a light scattering method, and the average particle size and the rate of change of the average particle size are shown in Table 1. . This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

(Comparative Example 3) In the basic compound A, fused spherical silica powder 2 was fused with fused spherical silica 5 (average particle size of 0.
65 μm, maximum particle size 1.3 μm, particle size less than 1 μm Component: 97% by weight)
Automatic mortar of γ-glycidoxypropyltrimethoxysilane (volume 4 liters, rotation speed: pestle 60 rpm, mortar:
The treatment was performed at 6 rpm for 10 minutes. At this time, the average particle size of the fused spherical silica powder 5 as a raw material and the fused spherical silica powder 5 treated with an automatic mortar were measured by a light scattering method, and the average particle size and the change rate of the average particle size are shown in Table 1. It was This was premixed with the remaining components of the basic compound A in a Henschel mixer, and an epoxy resin molding material was obtained in the same manner as in Example 1 except for the above. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

(Comparative Example 4) A Henschel mixer (capacity 15 liters, rotation speed 100
Pre-mixed for 5 minutes at 0 rpm and 10 ° C., meshed in the same direction and twin-screw extrusion kneader (screw diameter D = 30 m)
m, extruder shaft length = 1 m, kneading disc length = 6
D, screw rotation speed 300 rpm, discharge amount 20 kg /
An epoxy resin molding material was obtained by the usual production method of heating and kneading in h). The fluidity and package reliability of the obtained epoxy resin molding material were evaluated, and the results are shown in Table 1.

(Comparative Example 5) Of the basic compound A, γ-
Glycidoxypropyltrimethoxysilane and fused spherical silica powder 2 were premixed for 10 minutes in a Henschel mixer and this was premixed in the Henschel mixer with the rest of the basic formulation A, otherwise as in Example 1. An epoxy resin molding material was obtained in the same manner. The fluidity and package reliability of the obtained material were evaluated, and the results are shown in Table 1.

[0031]

[Table 1]

[0032]

As described above, according to the present invention, even if the filling rate of the inorganic filler is high, the fluidity during semiconductor encapsulation molding is good, and the package reliability after encapsulation molding is high. A stable epoxy resin molding material for semiconductor encapsulation can be stably manufactured.

Continued front page    F-term (reference) 4F070 AA46 AC22 AC23 AD04 AD06                       AE01 FA03 FA14 FB06 FC03                       FC06                 4J002 CC032 CD051 CD061 CD071                       CE002 DJ006 DJ016 EN027                       EU117 EV237 FB136 FB156                       FD016 FD090 FD142 FD157                       GQ05                 5F061 AA01 BA01 CA21 DE04

Claims (3)

[Claims] 1. An epoxy resin, a phenol resin, and an inorganic charge.
Contains at least filler, curing accelerator, and coupling agent
Epoxy for semiconductor encapsulation with a machine filler content of 90% by weight or more
In the method for producing a resin molding material, among the inorganic fillers,
Average particle size D ₅₀Inorganic fillers with a particle size of 0.5 μm or less
Change rate of average particle size is 10% or less in the presence of a pulling agent
Shear shear force in the range of
After premixing with machine filler and other ingredients, heat kneading
Epoxy resin molding material for semiconductor encapsulation characterized by
Manufacturing method. 2. Epoxy resin and phenol resin, inorganic charge
Contains at least filler, curing accelerator, and coupling agent
Epoxy for semiconductor encapsulation with a machine filler content of 90% by weight or more
In the method for producing a resin molding material, among the inorganic fillers,
Average particle size D ₅₀Inorganic fillers with a particle size of 0.5 μm or less
Change rate of average particle size is 10% or less in the presence of a pulling agent
Shearing force is applied in the range of 0.1 to 1 and the inorganic filler is 0.1 to 1.
Premix 0% by weight with the rest of the inorganic filler and other ingredients
For semiconductor encapsulation, characterized by heating and kneading after combining
Manufacturing method of epoxy resin molding material. 3. An epoxy resin molding material for semiconductor encapsulation, which is obtained by the manufacturing method according to claim 1.